Re: lua_getglobal function argument

[Duncan Cross <duncan.cross@...>]

On Wed, Feb 8, 2012 at 10:35 AM, saito yutaka <melody.pea@gmail.com> wrote:
> Hello .
> I am trying to read lua.c to want know how lua works.
> And I want to ask about lua_getglobal function.
>
> I find a this code .
>  lua_getglobal(L, firstline ? "_PROMPT" : "_PROMPT2");
>
> I know that this code means get a value PROMPT("> ") or PROMPT2(">> ") .
> But why does it use underscore [ _ ] front of global names ?
>
> Thanks.
> Yutaka

Starting with one underscore is just a convention to indicate
"internal" global variables that relate to the host
application/current context, rather than the specific program being
run. For example _VERSION[1]. It is recommended that a piece of pure
Lua code should avoid using this convention when defining its own
global variables.

[1] http://www.lua.org/manual/5.1/manual.html#pdf-_VERSION

-Duncan